C. E. Nord

Development of the faecal anaerobic microflora after Caesarean section and treatment with antibiotics in newborn infants

SummaryQualitative and quantitative anaerobic cultures were performed on faecal samples from 27 normal full-term newborn infants; from 32 preterm infants during intensive or intermediate care, not treated with antibiotics; and from 106 mostly preterm newborns, treated with antibiotics for various reasons. There were no major differences between the children in the first two groups. In these, Caesarean section led to a lower isolation rate of bifidobacteria and a much lower incidence ofBacteroides spp. During antibiotic treatment anaerobic bacteria were isolated from only 10% of the infants. After treatment, there was a slow regrowth of bifidobacteria, butBacteroides spp. were not usually re-established. There was a colonisation of infants delivered by Caesarean section with newLactobacillus spp. after treatment. In particularBacteroides colonisation may be facilitated and more stable if it occurs during passage through the birth canal.ZusammenfassungVon 27 reifen Neugeborenen, 32 Frühgeborenen in Intensivtherapie oder klinischer Behandlung ohne Antibiotikatherapie sowie von 106 vorwiegend Frühgeborenen, die aus verschiedenen Gründen mit Antibiotika behandelt werden mußten, wurden qualitative und quantitative Kulturen von Stuhlproben angefertigt. Die Kinder der ersten beiden Gruppen wiesen keine wesentlichen Unterschiede auf. Bei Kaiserschnitt-Kindern war die Isolationsrate an Bifidobakterien geringer und die Isolationsrate anBacteroides spp. erheblich geringer als bei Kindern, die vaginal entbunden wurden. Während der Antibiotikatherapie wurden von nur 10% der Kinder anaerobe Bakterien isoliert. Nach der Antibiotikatherapie holten die Bifidobakterien langsam an Wachstum auf, doch siedelten sich meist keineBacteroides spp. an. Kinder, die durch Kaiserschnitt entbunden worden waren, wiesen nach der Antibiotikatherapie eine Besiedelung durch neueLactobacillus spp. auf. Die Kolonisation mitBacteroides spp. scheint bei Passage durch den Geburtskanal leichter und stabiler zu erfolgen als bei Kaiserschnitt-Entbindung.

Isolation of β-lactamase-producing Bacteroides strains associated with clinical failures with penicillin treatment of human orofacial infections

Abstract Five patients with orofacial infection which failed to respond to penicillin therapy are described. In each instance, β-lactamase producing Bacteroides strains were found. All strains were resistant to penicillin but sensitive to clindamycin and tinidazole. In two cases, extended surgical treatment cured the patient, but in the other three cases additional clindamycin therapy was required.

Serum antibody response to clostridium difficile toxins in patients with clostridium difficile diarrhoea

SummaryConsecutive serum samples from 61 patients withClostridium difficile diarrhoea were investigated for antibody response toC. difficile toxins A and B in an indirect enzyme immunoassay (ELISA) and in a neutralization assay againstC. difficile cytotoxin. Sera from 64 blood donors, elderly healthy females and patients with other known intestinal enteropathogens served as controls. An immune response was detected by ELISA in approximately half of the patients withC. difficile diarrhoea. The specificity of the ELISA was 94% or 97%, depending on the control material used. Furthermore, a correlation was found between clinical recovery without relapse ofC. difficile diarrhoea and high IgG titers to toxin B in the ELISA, and/or appearance of neutralizing antibodies. It is concluded that the ELISA for detection of serum antibodies toC. difficile toxins may be of diagnostic value in combination with the conventional tissue culture assay for cytotoxin in stool. High ELISA IgG titres to toxin B and/or the appearance of neutralizing antibodies may also be a positive prognostic sign in patients withC. difficile diarrhoea.ZusammenfassungVon 61 Patienten mitClostridium difficile-Diarrhoe wurden konsekutive Serumproben mit einem indirekten Enzymimmunassay (ELISA) und einem Neutralisationstest fürC. difficile Cytotoxin auf die Antikörperantwort gegen die Toxine A und B vonC. difficile untersucht. Als Kontrollen wurden Seren von 64 Blutspendern, älteren gesunden Frauen und Patienten, die an Krankheiten durch andere bekannte enteropathogene Erreger litten, verwendet. Bei annähernd der Hälfte der Patienten mitC. difficile-Diarrhoe wurde mittels ELISA eine Immunantwort entdeckt. In Abhängigkeit vom Kontrollmaterial ergab sich für den ELISA-Test eine Spezifität von 94% oder 97%. Bei Patienten, die sich ohne Rezidiv von derC. difficile-Diarrhoe erholten, bestand eine Korrelation zu hohen IgG-Titern gegen Toxin B im ELISA-Test und/oder Auftreten von neutralisierenden Antikörpern. Daraus läßt sich schließen, daß die Bestimmung der Antikörper gegenC. difficile-Toxine im Serum mit ELISA in Kombination mit dem herkömmlichen Gewebekultur-Test auf Cytotoxin von diagnostischem Wert ist. Hohe ELISA IgG-Titer gegen Toxin B und/oder das Auftreten neutralisierender Antikörper im Serum können bei Patienten mitC. difficile-Diarrhoe als positives prognostisches Zeichen gewertet werden.

Norfloxacin binds to human fecal material.

Earlier studies have reported very high (120 to 2,700 mg/kg) concentrations of norfloxacin in feces after therapeutic doses. MICs for fecal microorganisms are with few exceptions far below these levels. Nevertheless, clinical investigations show that the main part of the aerobic gram-positive and the anaerobic microflora remains unaffected after norfloxacin administration. In this study, the binding of [14C]norfloxacin to fecal material was analyzed. The binding of a group of nonlabeled quinolones to feces and the interactions between Enterococcus faecium, Bacteroides fragilis, and norfloxacin were also investigated. The results showed that norfloxacin has the ability to bind to feces. The specific binding was reversible, saturated after 90 min of incubation at 37 degrees C, and increased linearly with fecal concentration. Scatchard plots and nonlinear regression computer analyses revealed two different binding classes. The primary specific binding had a dissociation constant (KD) of 1.0 microM and a maximal binding capacity (Bmax) of 0.12 mumol/g of feces. The KD and Bmax of the secondary, more unspecific binding were 450 microM and 11.8 mumol/g of feces, respectively. The binding of unlabeled ciprofloxacin, enoxacin, ofloxacin, pefloxacin, and norfloxacin to feces was comparable to that of [14C]norfloxacin. The results of norfloxacin binding to suspensions of B. fragilis suggested that the main part of the binding is to the bacterial fraction of feces. In the presence of 8.0 g (dry weight) of B. fragilis per liter, the MBC of norfloxacin for E. faecium increased from 8 to 256 micrograms/ml. The finding of the present study indicated that binding of norfloxacin to feces may explain the paradox of high fecal concentrations of norfloxacin versus the actual effect on the normal gastrointestinal microflora.

Formation of Beta-Lactamase in Bacteroides fragilis: Cell-Bound and Extracellular Activity

Nine strains of Bacteroides fragilis were cultivated in stirred fermentors and tested for their ability to produce β-lactamase. There was a correlation between formation of β-lactamase and high values of the minimal inhibitory concentration against β-lactam antibiotics. B. fragilis strain B70 was used for optimizing the production of β-lactamase. The highest bacterial yield was obtained in a proteose peptone-yeast extract medium. Optimal conditions for growth and β-lactamase production were obtained at 37 C and pH 7.0. The β-lactamase was released into the surrounding medium during the growth period to about 50%. Osmotic shock released about 20% of the total activity, and remaining activity was found in the cytoplasmic fraction. Substrate profile studies on four β-lactamase-producing strains showed that the enzymes were mainly cephalosporinases. They are inhibited by cloxacillin, p-chloromercuribenzoate, and iodine. Analytical isoelectric focusing in polyacrylamide gel gave an isoelectric point of 4.9 ± 0.2 for three of the strains and 5.6 ± 0.2 for one. Comparison with β-lactamases from aerobic gram-negative species with regard to isoelectric points showed no similarities. Also the molecular weight of the β-lactamase from strain B70 of 43,000 indicates that this is a new class of β-lactamase.

Antibiotic sensitivity of theBacteroides fragilis group in Europe

Rates of resistance to 12 antibiotics were determined for 1,289 isolates of theBacteroides fragilis group submitted in 1988–1989 by 22 laboratories in 15 European countries. There was no resistance to metronidazole (breakpoint 8 mg/l) and only one isolate was resistant to chloramphenicol (breakpoint 8 mg/l). Resistance was uncommon for imipenem (0.3 % at > 4 mg/l), amoxicillin/clavulanate (1 % at > 8 mg/l), cefoxitin (3 % at > 32 mg/l), mezlocillin (6 % at > 64 mg/l) and clindamycin (9 % at > 4 mg/l). Resistance was the rule for ampicillin (93 % at > 4 mg/l), ciprofloxacin (56 % at > 4 mg/l) and tetracycline (64 % at > 4 mg/l).Bacteroides fragilis, the commonest species, was generally the most sensitive: resistance of this organism was uncommon for cefotetan (4 % at > 32 mg/l) and ceftazidime (12 % at > 32 mg/l) to which the other species were more often resistant. There were small but significant differences between laboratories and countries for many of the antibiotics. Regionally the most striking differences were for clindamycin where resistance inBacteroides fragilis was most common in the South and for tetracycline where resistance inBacteroides fragilis, Bacteroides thetaiotaomicron andBacteroides uniformis was least common in the North.

Effects of prophylactic administration of cefaclor on transient bacteremia after dental extraction

This study was undertaken to investigate the effects of prophylactic administration of cefaclor on bacteremia after dental extraction. Thirty-nine patients were randomly assigned to receive either 1 g cefaclor (19 patients) or placebo (20 patients) 1 h prior to dental extraction. Blood samples for microbiological investigation were collected before, during, and 10 min after surgery, and were processed by lysis filtration under anaerobic conditions. The incidence of bacteremia with viridans streptococci was 79% in the cefaclor group and 50% in the placebo group during extraction. No difference in the incidence or magnitude of bacteremia was observed when the two patient groups were compared.

Yeast colonization in the oral cavity and feces in patients with denture stomatitis

An investigation was undertaken of 77 denture wearers to study the incidence of yeasts in the angles of the mouth, denturebearing mucosa, denture base, the throat and the gastrointestinal tract. Fifty-one denture wearers exhibited denture stomatitis and 26 showed no clinical signs of inflammation of the palatal mucosa (controls). In addition the influence of oral local treatment with an antifungal agent (Mycostatin®) on the yeast flora in the same sites was studied in denture wearers with denture stomatitis. The findings suggest a higher rate of yeast colonization in the mouth (100% compared to 40%) and feces (71% compared to 35%) in denture wearers with denture stomatitis than in denture wearers without stomatitis. Similar species of yeasts, predominantly Candida albicans, C. tropicalis and Torulopsis glabrata were identified among the isolates from the oral sites, throat and feces in denture wearers with stomatitis. In denture wearers without stomatitis the yeast species isolated from the oral sites and...

Comparison of Oral and Vaginal Metronidazole Therapy for Nonspecific Bacterial Vaginosis

A prospective, randomized, nonblind study was performed to compare the efficacy of a 7-day vaginal regimen with 500 mg metronidazole (Flagyl) once a day and that of oral treatment with 400 mg metronidazole twice daily for 7 days in the treatment of nonspecific bacterial vaginosis. No treatment was given to the sexual partners and there was no restriction of sexual intercourse. 38 women completed the study and at follow-up after 4 weeks, women receiving vaginal therapy had a cure rate of 79% compared with 74% in the women on oral therapy. Cure rates were lower among users of an intrauterine contraceptive device (57 versus 88% among nonusers). The occurrence of lactate-producing bacteria (lactobacilli and aerobic streptococci) in the vagina was significantly higher in women after vaginal compared with oral therapy. Gardnerella vaginalis was isolated in 58% of the women after vaginal and in 44% of the women after oral treatment. It is concluded that vaginal application of 500 mg metronidazole daily for 7 days is equally effective as oral administration in the treatment of bacterial vaginosis.

Evaluation of five test-kits —API, AuxoTab, Enterotube, PathoTec and R/B— for identification ofEnterobacteriaceae

Five test-kits—API, AuxoTab, Enterotube, PathoTec and R/B-have been compared for accuracy in individual tests and for identification on the genus or species level with conventional biochemical tests on 329 strains belonging toEnterobacteriaceae. The API system was found to be the most reliable followed by Enterotube, R/B, PathoTec and AuxoTab. The API system was used in parallel with the standard biochemical testing in the routine bacteriological work for identification of aerobic gramnegative fermentative rods from clinical specimens during a 10 weeks period. 2351 of 2404 strains were identified with this system and the system was found to be very reliable.